Interconnect Corrosion In Steam Containing Fuel Gas

Degradation in planar SOFCs is mainly driven by oxidation of metallic interconnects. This study investigate oxidation behavior of three ferritic steels Crofer (R) 22APU, Crofer (R) 22H, AISI 441 and a chromium-based alloy CFY in anode gas environment in a temperature range between 725 and 875 degrees C. The experiments were carried out under variation of the steam content. Oxide scale has been observed after different exposure times in order to define proper accelerated oxidation conditions and to investigate microstructure change of these materials. Both gravimetric measurements and FESEM/EDX data, as well as polished micro image cross sections were analyzed to characterize the oxidation kinetics and the microstructure of the oxide scales and interconnect materials. The results of the oxide scale formation under the anode gas conditions in tested Crofer (R) 22APU and CFY samples are compared with data derived from operated SOFC stacks.